1. Field of the Invention
The present invention relates to an ink jet printer and particularly, to an ink jet printer in which an ink is jetted after being heated.
2. Description of the Related Art
Recently, an ink jet printer has been widely used because images can be easily formed at a low cost in comparison to a method such as a gravure printing method or a flexographic method which needs a plate.
In the field of performing image recording on goods or packing material for goods by using the ink jet printer, material with no ink absorptivity such as resin or metal is generally used for goods or packing for goods. There is known a ink jet printer of photo curable type in which a recording medium made from material with no ink absorptivity and photo curable ink are used, and for example, the ink jetted onto the recording medium is irradiated with light such as ultraviolet rays to cure and fix the ink thereon (for example, refer to JP-2002-283545A).
JP-2002-283545A discloses an example of an ink jet printer in which photo curable ink is used. Specifically, a recording apparatus in JP-2002-283545A is provided with a rotatable and transparent dram shaped intermediate transfer body and a printing head facing the outer periphery of the intermediate transfer body. In a recording operation, ink is jetted from the printing head onto the outer periphery of the intermediate transfer body and the ink placed on the intermediate transfer body is irradiated with light from outside of the intermediate transfer body, and thereafter, the ink irradiated with light is transferred onto the recording medium while rotating the intermediate transfer body. Such a recording method is successful in preventing deterioration of image quality such as beading or bleeding as well as transferring the ink with optimum viscosity onto the recording medium by adjusting the viscosity of the ink placed on the intermediate transfer body.
Generally, photo curable ink has high viscosity in a normal room temperature (around 18 to 28° C.), therefore having a difficulty in stably jetting the ink. For stably jetting the ink, ink viscosity is preferably 3 to 20 mPas, so that an ink jet printer has been developed in which photo curable ink is heated to 40 to 80° C. to have low ink viscosity of 3 to 20 mPas before being jetted.
However, when the photo curable ink with decreased viscosity is jetted from the printing head, the ink spreads until being irradiated with light after placed on the recording medium, thereby causing images to blur.